The present invention relates to a spring connector which has high reliability and can be manufactured at low cost.
FIGS. 9A to 11C show a conventional spring connector disclosed in Japanese Patent Publication No. 2003-17173A.
The conventional spring connector comprises a plate-shaped terminal 10 made of conductive material, a conductive pin 12 which can slide with respect to the terminal 10, a coil spring 14 which is provided between the terminal 10 and the conductive pin 12 in a compressed state, and a holder 16 formed of insulating resin.
The terminal 10 is formed of an elongated sheet metal which has been folded to form a substantially U-shape as shown in FIG. 11C. A dented part 10a which opens in a forward direction is formed in one of the folded halves of the terminal 10, and a small protrusion 10b is formed at a center of a bottom edge of the dented part 10a, as shown in FIGS. 11A and 11B. The other of the folded halves serves as a connecting part 10c to be fixed by soldering or so to a circuit board (not shown).
The conductive pin 12 has a plunger part 12a having a relatively small diameter at its tip end side and a protruded part 12b having a relatively large diameter at its base end side. This protruded part 12b is provided with axially extending grooves 12c on both sides thereof. These grooves 12c are adapted to be engaged with opposed inner edges of the dented part 10a in the terminal 10, and the conductive pin 12 is arranged so as to slide with respect to the terminal 10 along the grooves 12c, as guides for the sliding movement. The conductive pin 12 is further provided with a blind hole 12d in an axial direction form its base end face. The terminal 10 and the conductive pin 12 may be plated with gold as required.
Then, the conductive pin 12 is slidably incorporated into the holder 16 such that a tip end of the plunger part 12a is projected from the holder 16 so as not to be pulled out. The terminal 10 appropriately fixed to the conductive pin 12 is also incorporated into the holder 16. The conductive pin 12 is so designed as to be slidable in an axial direction thereof and in a diagonal direction with respect to a bottom face of the holder 16. In this state, the coil spring 14 is provided in a compressed state between the conductive pin 12 and the bottom edge of the dented part 10a in the terminal 10, having its one end inserted into the blind hole 12d in the conductive pin 12 and the other end blocked by the protrusion 10b at the center of the bottom edge of the dented part 10a in the terminal 10 so as not to be displaced. Moreover, the connecting part 10c of the terminal 10 is disposed on the bottom face of the holder 16.
In this example, when a contact terminal 18 comes into contact with the tip end of the plunger part 12a of the conductive pin 12 in a direction parallel with the bottom face of the holder 16, as shown in FIG. 9B, the conductive pin 12 moves diagonally downward, while compressing the coil spring 14 along the inner edges of the dented part 10a in the terminal 10, as the guides. On this occasion, a force F in FIG. 9B is exerted on the conductive pin 12 in a direction of prying it, and the grooves 12c of the conductive pin 12 are strongly pressed against the inner edges of the dented part 10a in the terminal 10. In this manner, electrical connection between the conductive pin 12 and the terminal 10 can be reliably obtained.
In order to reliably obtain the electrical connection between the conductive pin 12 and the terminal 10, it is necessary for the conductive pin 12 to be pushed into the holder 16 in a direction inclined at a certain angle with respect to the bottom face of the holder, but not in parallel with the bottom face. In other words, the direction of pushing in the conductive pin 12 is so set as to be inclined at a certain angle with respect to a direction of movement of the contact terminal 18. Consequently, a height of the conductive pin 12 from the bottom face is increased by the amount of the inclination.